1. Field of the Invention
The present invention relates to a structure for interconnecting a plug and jack by inserting the plug into the jack and, more particularly, to a plug-jack connecting structure for interconnecting a plug and a jack which prevents the unexpected detachment of the plug from the jack even when the plug-jack connecting structure connecting the plug to the jack is vibrated or shocked.
2. Description of the Prior Art
Electronic equipment, such as a car phone, a TV, etc., is put into an operative state when a plug of the electronic equipment is inserted into a jack mounted on the front panel of the car. The connection between the plug and the jack is usually made by elastic contact between terminals disposed along a plug receiving hole of the jack and the periphery of the plug. In other words, a plurality of terminals are mounted inside of the jack and the plurality of terminals serve as a ground terminal and as positive and negative electrode terminals.
Furthermore, the terminals are partly bent or punched to form elastic contact portions. When a multi-polar plug is inserted into the jack of such a construction as above-described, respective terminals elastically contact the corresponding electrodes of the plug to establish electric connections therewith and to firmly hold the plug in the jack. However, the forces exerted on the periphery of the plug by the elastic contact of the plug and the terminals make it highly likely that the plug will detach from the jack due to vibrations and shocks created during traveling, which often results in an interruption of telephone communication, TV reception, etc.
To overcome such a disadvantage, the plug is conventionally screwed into the jack. A conventional screw type plug-jack connecting structure includes a male screw thread which extends outwardly from the outer surface of a sleeve that guides the plug into the jack. A conventional screw type plug-jack connecting structure also includes a ring mounted on the plug at one end thereof and a female screw thread which has been extruded inwardly from the inner surface of the ring.
With such a screw type plug-jack connecting structure, the ring carried by the plug is butted end-to-end against the sleeve of the jack and then rotated into threaded engagement with the sleeve, so that the plug and the sleeve can be firmly coupled with each other. Thus, the conventional screw type plug-jack connecting structure provides the coupling between the plug and the sleeve of the jack by screwing in order to preclude the possibility of the plug accidentally becoming detached from the jack due to vibrations and shocks.
With the conventional screw type plug-jack connecting structure, however, the ring mounted on the plug needs to be frequently rotated into threaded engagement with the sleeve, thus making the connecting operation cumbersome. More particularly, in the case of connecting the plug to the sleeve during driving, the driver's attention is at least momentarily diverted from his/her driving, thus posing the danger of a traffic accident.
Another problem of the conventional screw type plug-jack connecting structure is the need for forming screw threads on both of the sleeve and the ring. The use of metal for the sleeve and the ring so that the male and female screw threads can be cut into the outer & inner surfaces thereof, respectively, inevitably increases the manufacturing cost of the conventional screw type plug-jack connecting structure. On the other hand, the formation of screw threads, during the formation of dies by molding of a resin material, would require highly developed molding techniques and complicated molding machine which involve a screw-wise transfer of one of the dies during molding. This would also raise the manufacturing cost of the conventional screw type plug-jack connecting structure.